Vaporization cooling of electrical apparatus



March 23, 1965 J. c. DuT'roN VAPORIZATION COOLING OF' ELECTRICAL APPARATUS Filed Sept. 3, 1963 United States Patent O l 3,174,540 VAPORIZATION COOLING F ELECTRICAL APPARATUS .lohn C. Dutton, Rome, Ga., assignor to General Electric Company, Schenectady, N.Y., a corporation of New York Filed Sept. 3, 1963, Ser. No. 305,999 3 Claims. (Cl. 16S- 105) This invention relates to vaporization cooling and more particularly to improvements in the vaporization cooling of electrical apparatus such as transformers.

By vaporization cooling is meant using the latent heat of vapon'zation of a liquid rather than its specific heat for cooling purposes. In such systems the vapor is condensed in a cooler and the liquid returned to the area or part to be cooled by vaporization, the cycle or circulation being maintained by a pump.

In accordance with this invention, the pump is eliminated and by a special arrangement of finned cooling tubes containing a volatile liquid the cooling cycle is selfrepeating.

An object of the invention is to provide a new and improved cooling system.

Another object of the invention is to eliminate the pump or its equivalent in a vaporization cooling system.

A further object of the invention is to provide a simple, etiicient, long lived vaporization cooling system having no movable mechanical parts.

The invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the drawing,

FIG. 1 is an elevational sectional view through a transformer embodying the invention,

FIG. 2 is an enlarged side view of one of the finned cooling tubes, and

FIG. 3 is an enlarged view of the inner end of such a finned tube.

Referring now to the drawing, and more particularly to FIG. l, there is shown therein a transformer 1 comprising a core and coil assembly 2 enclosed in a sealed tank 3. Extending through walls of the tank 3 are a plurality of finned cooling tubes 4. As shown, these tubes are inclined upwardly from their inner ends to their outer ends and their inner ends are staggered so that the higher ones are longer than the lower ones. However, in all cases the inner ends of the tubes are vertically over the core and coil assembly 2.

As shown more clearly in FIG. 2, the tubes 4 are sealed and are partially filled with any suitable volatile liquid 5. A preferred composition is trichlorotrifluoroethane (C2CI3F3). The portions of the tubes 4 extending outside the wall of the tank 3 are provided with axially spaced cooling tins 6 extending radially in all directions from the tube.

As shown more clearly in FIG. 3, the portion of the tube 4 inside the tank is preferably but not necessarily provided with upwardly extending fan-like fins 7.

In operation, there is a body of any suitable cooling and insulating uid 8 in the tank 3 which has a boiling point at the approximate desired operating temperature considering all system parameters. A preferred composition of this insulating and vaporization cooling material is per- 3,174,540 4 PatentedMar. 23, 1965 ICC.

fluorocyclic ether (CBFISO). Thus this fluid when in liquid phase and in contact with the core and coils will be vaporized, the latent heat of Vaporization serving to extract heat from the core and coil. The vaporized iiuid on rising condenses on the fan-like fins 7 of the tubes 4, then runs down their surfaces and collects on the bottom of the respective tubes along which it runs until it drops off as liquid and falls onto the core and coils where it is revaporized and the cycle is repeated.

Heat is removed from the entire apparatus through the operation of the volatile liquid 5 in the tubes in that as the vaporization cooling fluid 8 condenses on the fins 7 and gives up its heat thereto the volatile liquid 5 or a part thereof becomes heated and volatilized and rises and passes out to the outer end of the tubes 4 where it is cooled by the iins 6 in the relatively cool ambient air of the atmosphere whereupon it recondenses and runs back by gravity as relatively cool liquid to the inner end of the tubes 4 thus maintaining them at a temperature below the condensing temperature of the vaporization cooling fluid 8.

If desired or found necessary, a trough-like receptacle 9 may be supported or hung below and parallel with the inner portions of the tubes 4 so as to catch any condensate dripping from the bottom of the tubes 4 before it reaches the end thereof, such collected condensate will then run down the trough to its lowermost inner end and drip onto the core and coils.

It is desirable to prevent condensation of the vaporization cooling iiuid 8 on the inner tank walls but in the event that condensed vapor collects as liquid at the bottom of the tank it can be returned to the top of the core and coil by any suitable means such as a pump and conduit.

While there has been shown and described a particular embodiment of the invention, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention, and therefore it is intended by the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. In combination, a sealed transformer tank containing a core and coil assembly, a volatile insulating liquid in said tank insuiiicient in liquid volume to effect appreciable immersion of said assembly, said insulating liquid being vaporizable at a predetermined desired temperature at which said core and coil assembly are to be maintained, a plurality of sealed cooling tubes partially filled with a volatile cooling liquid, said tubes extending through a wall of said casing, said tubes being inclined upwardly from their inner ends to their outer ends, the inner end of each tube being vertically above said core and coil assembly, axially spaced fins attached to said tubes outside said tank and extending radially therefrom in all directions, and axially spaced fins attached to said tubes inside said tank and extending radially thereof in all upward directions only, whereby vapors of the insulating liquid in said tank are condensed on the inner ends of said tubes and said upwardly extending fins and the condensed liquid runs along the bottoms of said tubes to their inner and lowermost ends and drips olf onto said core and coil assembly there to be revaporized by the heat of said assembly and cool said assembly by Vaporiztion.

2. The combination as defined in claim 1 in which there is a trough beneath each tube inside said tank and parallel therewith for collecting liquid condensate dripping from the bottom of said tube before it reaches the inner end of said tube and discharging it above said core and coil assembly.

3. The combination as defined in claim 1 in which some of said tubes are above others, the higher tubes being longer on the inside of said tank than the lower tubes.

References Cited bythe Examiner UNITED STATES PATENTS Gay 165-32 X Marshall 62-119 X Young 62-287 Bailey 62-285 Goltsos et al. 165-105 X CHARLES SUKALO, Primary Examiner. 

1. IN COMBINATION, A SEALED TRANSFORMER TANK CONTAINING A CORE AND COIL ASSEMBLY, A VOLATILE INSULATING LIQUID IN SAID TANK INSUFFICIENT IN LIQUID VOLUME TO EFFECT APPRECIABLE IMMERSION OF SAID ASSEMBLY, SAID INSULATING LIQUID BEING VAPORIZABLE AT A PREDETERMINED DESIRED TEMPERATURE AT WHICH SAID CORE AND COIL ASSEMBLY ARE TO BE MAINTAINED, A PLURALITY OF SEALED COOLING TUBES PARTIALLY FILLED WITH A VOLATILE COOLING LIQUID, SAID TUBES EXTENDING THROUGH A WALL OF SAID CASING, SAID TUBES BEING INCLINED UPWARDLY FROM THEIR INNER ENDS TO THEIR OUTER ENDS, THE INNER END OF EACH TUBE BEING VERTICALLY ABOVE SAID CORE AND COIL ASSEMBLY, AXIALLY SPACED FINS ATACHED TO SAID TUBES OUTSIDE SAID TANK AND EXTENDING RADIALLY THEREFROM IN ALL DIRECTIONS, AND AXIALLY SPACED FINS ATTACHED TO SAID TUBES INSIDE SAID TANK AND EXTENDING RADIALLY THEREFROM IN ALL UPWARD DIRECTIONS ONLY, WHEREBY VAPORS OF THE INSULATING LIQUID IN SAID TANK ARE CONDENSED ON THE INNER ENDS OF SAID TUBES AND SAID UPWARDLY EXTENDING FINS AND THE CONDENSED LIQUID RUNS ALONG THE BOTTOMS OF SAID TUBES TO THEIR INNER AND LOWERMOST ENDS AND DRIPS OFF ONTO SAID CORE AND COIL ASSEMBLY THERE TO BE REVAPORIZED BY THE HEAT OF SAID ASSEMBLY AND COOL SAID ASSEMBLY BY VAPORIZTION. 